Preliminary evaluation of a commercially available rapid immunochromatographic method for the detection of IgM antibody response to chikungunya and dengue viruses
Abstract number: P2183
Rossini G., Cavrini F., Luconi L., Pierro A., Spataro N., Angelini R., Benini F., Sambri V.
Objectives: Chikungunya virus (CHIKV) belongs to the family of arthropod-borne viruses and it's transmitted to humans by Aedes mosquitoes in tropical and sub-tropical areas. In August 2007, the first epidemic outbreak within the territory of the EU has started in the province of Ravenna in North-Eastern Italy. Up to today more than 200 laboratory confirmed cases have been reported and more than 1000 patients underwent laboratory investigation. The large diffusion of Aedes albopictus (the tiger mosquito) in Northern and Central Italy was the condition that allowed the epidemic diffusion of CHIKV. The laboratory diagnosis is performed by detecting the viral RNA in blood by RT-PCR within the first 6 days after onset and by serological evaluation immediately after this period.
Methods: The presence of an IgM specific response to CHIKV and Dengue was evaluated by two different methods: immunofluorescence (IIFT) test (Euroimmun) and a newly available immunochromatographic (IC) method (CTK OnSite Duo) that is designed to distinguish between IgM response to CHIKV and Dengue. The samples used were obtained, during the recent outbreak, from 67 different patients with clinical and epidemiological evidence of suspected acute CHIKV infection (high fever and multiple arthralgia) living in the area of Ravenna.
Results: 45 samples were detected negative for IgM against CHIKV and Dengue by using IIFT and 50 specimens were scored as negative by IC. No IgM reaction against Dengue were detected. The use of IIFT allowed to identify as positive for CHIKV 22 samples but only 17 were confirmed with the IC method. The relative sensitivity of IC (versus IIFT chosen as the reference method) is 90%. The relative specificity of IC is 100%.
Conclusion: The use of a quick and simple test, like the IC evaluated in this study, could be proposed as a "field" method to rapidly discriminate the true CHIKV infections during epidemic outbreaks. The availability of a rapid response is useful for the appropriate targeting of the environmental interventions devoted to the control of vector mosquitoes. A correct environmental intervention has been demonstrated as the most efficacious methods to stop the spread of CHIKV during the recent outbreak in Italy. The use of "field" tests is not sufficient to achieve a correct diagnosis of CHIKV infection and the use of more sensitive laboratory tests such as IIFT is mandatory to confirm the clinical suspect.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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